The present invention relates to machine tools, and, more particularly, to machine tools for simultaneously machining a stack of plate-like workpieces.
In Herb et al. U.S. Pat. Nos. 4,270,253 and 4,462,147, there is described a machine tool for simultaneously mounting a stack of plate-like workpieces upon a base member, riveting the plate like workpieces thereto, drilling and riveting the workpieces to the base member, machining the group of workpieces by movement of the assembled stack relative to a machining station, and thereafter drilling the rivets so that the individual workpieces may be disassembled from the stack. This type of machine has proven highly satisfactory for machining of a multiplicity of relatively thin workpieces with similar contours. As described in the Herb et al. patents, it is generally necessary to replace the router bit or the like with different tools to enable the cutting of various contours which might be required in a particular workpiece.
In the machine illustrated in the aforementioned Herb et al. patents, the machine tool is one which has a series of stations between which the workpieces would be moved to effect the initial drilling, to effect riveting, to effect the machining, and to effect drilling of the rivets after the machining and any intermediate drilling steps have been performed. As will be appreciated, multiple work stations complicate the problems inherent in achieving precision operations on a workpiece and the control system for effecting such motion of the workpieces among the several work stations. Moreover, the machine tool of the aforementioned Herb et al. patents required a relatively long shutdown of the machine tool to effect the required manual exchange of router bits or other tools in the machining station, and frequently of the drill bits employed in the drilling station.
It is an object of the present invention to provide a novel machine tool for simultaneously drilling, riveting and machining a multiplicity of workpieces in which guidance of the workpieces relative to the machining station is simplified and in which tools may be automatically and rapidly exchanged.
It is also an object to provide such a machine tool in which but two work stations are required and in which the tools in the machining station may be exchanged rapidly.
Another object is to provide such a machine tool in which there is included a tool storage assembly in which a multiplicity of drill bits and router bits are stored. A tool changer mechanism rapidly selects desired tools in accordance with computer instructions and effects the exchange of tools in the machining station.
A further object is to provide such a machine tool which enables safe and rapid operation and exchange of tools and which may be readily controlled by computer program.